The Microscope. 119 



slicing in three directions and thus getting a general view of the 

 internal structure of the skeleton. The microscope is essential to 

 the study of these Bryozoans, many of which are less than j^^ of an 

 inch in diameter and are complete colonies. Such are easily sec- 

 tioned in the matrix. — J. E. Stidham. 



It is not wonderful that the student of the Diatomacece often 

 becomes puzzled in such a labyrinth, when a single line, more or 

 less, or some slight difference in curvature is deemed sufficient to 

 warrant the constitution of a new species. — C Henry Cain. 



If the Diatomists were the only persons who delighted in cre- 

 ating species — out of nothing — we should have good reason to be 

 thankful.— i2. H. W. 



The object of this specimen is to demonstrate the assistance of 

 a ring on cover glass in focussing and finding small objects (dia- 

 toms). Make an alcoholic solution of any aniline color (for stock). 

 Take a little mucilage of gum arabic, add enough of the aniline 

 solution to color, then with a fine brush and the aid of a turn-table 

 the little ring is spun on a clean cover. The diatom or other object 

 is then placed in the center. Turn the cover upside down on a 

 wooden slide with an aperture in its center, place under the " scope" 

 and stick a little strip of gummed paper on this side so it may 

 indicate to the eye the direction in which the object lies. Then 

 place a drop of balsam on the center of a slide and mount in the 

 usual way. To hold cover-glass on turn-table, make a wooden slide 

 3x1 in. and mortise two holes i; inch from center, about gxf in., to 

 receive two little wedges of cork, with which the cover may be cen- 

 tered and securely held. I learned this method from Dr. W. A. 

 Clapp, of Indiana. To some of the members it will not be anything 

 new, but as I have not seen anything of the kind in the Club's 

 boxes it might interest and possibly be of use to some of our mem- 

 bers. — Charles Mitchell. 



Since ordinarily an object as delicate as a small louse (from 

 great horned owl), unprepared, is so transparent as to be of little 

 value, I attempted staining this specimen with carmine, with (to me) 

 very satisfactory results. After immersion in dilute acetic acid, 

 mounted it in glycerine as any other object. — W. H. Currier. 



When on a visit to Baltimore in March, 1886, I was talking 

 with Mr. F. W. McAllister as to why many persons could not see the 

 markings on diatoms. He said because they were astigmatic, 

 and asked why I could not put up a slide of arranged 

 diatoms as a test. This slide will give the direction in which one is 

 astigmatic. Use the lowest powers with which you can see the lines 



